Improvement in mandrels for bending metallic tubing



M. Lponum. Mandrlels for Bending Metallic Tubing.`

N0.` 166,294. PatentedUAug.3`,1l87l5.

4@ f fgfwegg UNITED STATES PATENT OtrEIruf:c

MORRIS L. ORUM, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN MANDRELS FOR BENDING METALLICTUBING.

Specification forming part of Letters PatentNo. 166,294, dated August 3,1875 application [tiled March 30, 1875.

To all whom t may concern:

Be it known that I, MORRIS L. ORUM, of the city and county ofPhiladelphia, in the State of Pennsylvania, have invented a certain newand useful Device for Bending Metal Pipe, of which the following` is aspecication: A

In the process of bending metal pipes or tubes, as heretofore practiced,it vhas been difficult to form a bend 'of regular circular section, byreason of the tendency of the pipe to atten at the bend inVtheoperation, and various expedients have been resorted t0 for thepurpose of obviating this difficulty. A process which has beenextensively practiced consists in lillin g the pipe with rosin oranalogous material, and removing the same by melting' after Vthe pipehas been bent. This process is, for obvious reasons, inconvenient, and,further, while involving the expenditure of considerable time, doeslnot, in all cases, prevent the iiattening ofthe pipe before mentioned.

My improvement is designed to provide a simple and convenient device bythe use of which pipes can be bent to any desired curvature withoutdattening or perceptible marking at the bend, as Well as, so far aspracticable, to guard against breakage of the pipe in the operation; towhich ends my improvement consists in a fiexible metallic mandrel,consisting of a spiral coil of wire, the section of which is such as topresent a fiattened surface on the exterior of the spiral, and which isof sufficient pliability to be readily bent into any curve desired,While at the same time possessing sufficient strength to act as aninternal support to the pipe, and prevent its deformation by the actionof the bending implement. This mandrel is introduced into the pipe,which is then bent by the ordinary means into the required curve, andthe iiexible mandrel withdrawn at the conclusion of the operation.

In the accompanying drawings, Figure 1 is a side view of a section ofpipe with my improved mandrel applied thereto; Fig. 2, a view, on anenlarged scale, of the same, taken at right angles to Fig. 1; and Fig.3, a section, on an enlarged scale, of a portionof the exiblc mandrel.

To carry Vout the objects of my invention, I

provide a flexible mandrel, A, which is formed of a spiral coil of stoutWire, the diameter of the coil being such that the mandrel may t easilywithin the pipe.

The wire used to form the mandrel should be either of a square,rectangular, or triangular section, or more or less iiattened upon theexterior surface of the spiral, so as to aiford as much bearing-surfaceas possible to the pipe, and the spiral should be coiled as closelyaspracticable for the same reason..

To bend a metal pipe, I select a flexible mandrel of suitable diameter,and introduce it into the pipe before commencing to bend it. I then bendthe pipe to the curvature required by the ordinary implements used forthe purpose, and afterward withdraw the mandrel from the pipe, which`Inhavefound, in practice, is not perceptibly marked or injured in theoperation, and the mandrel is ready for use with another pipe.

The mandrel can be readily withdrawn, after bending the pipe, byattaching one of its ends to a 1athe-spindle,and revolving it .in suchdirection as to reduce its diameter by screwing up its coils.

It is obvious: that in some cases, where additional strength is to beimparted to a pipe, the mandrel might beV allowed to remain in the pipeafter bending, if so desired; but, in general, it would be moredesirable to withdraw it after bending, as stated.

I have found in practice that by the use of my device I am enabled tobend metal pipes with ease and celerity, and am satisfied that itsintroduction will economize time, labor,

and material.

I do not desire to claim either a spiral coil of wire, or thecombination of the same with a pipe, as I am aware that flexible tubesfor gas, Ste., have been provided with an internal coil of wire, thepurpose thereof being to prevent the closing or collapsingl of the pipeWithout impairing its iiexibility.

I claim as my invention- A flexible mandrel for bending metallic pipe,consisting of a spiral coil of wire, the exterior surface of which isflattened, substantially as set forth.

MORRIS I.. oRUM.

Witnesses:

J. SNOWDEN BELL, GEO. H. Fox.

